Generalised Dystonia usually occurs in late childhood/early teens, it is unusual for it to start after the mid twenties have been reached. In the majority of cases symptoms will progress for about five years before stabilising. I was 19 when my Generalised Dystonia started, it started in my Jaw and then spread rather quickly. Though I had an episode of Oromandibular Dystonia back when I was 17.
There are several possible reasons why someone may develop Generalised Dystonia. In some cases it is referred to as Primary, this is when there is no identifiable cause other than genetic factors such as a mutation in the DYT1 gene. Secondary Dystonia is when there is an underlying cause for example another medical condition, stroke etc. Dystonia can be inherited, there is a 30% chance of developing the condition if a person has the mutated gene. There are several other genes which can cause Primary Generalised Dystonia.
Treatment of Generalised Dystonia normally involves a combination of Botox injections and medication. I find a combination of muscle relaxants and six weekly injections, extremely helpful. Levodopa is usually trialled for around two months to see if the Dystonia is Dopamine responsive. Deep Brain Stimulation is also used to treat the condition and can make a huge impact to the sufferers quality of life. Selection for this however is done very carefully to make sure that the patient is likely to benefit from the treatment as the surgery obviously carries many risks.
Below is an image of one of full body spasms.